Multi-fill grease gun



April 4, 1961 E. P. SUNDHOLM 2,973,151

MULTI-FILL GREASE GUN Filed July 1, 1957 I I I, 20 ,4

/N VE N TOR United States Patent 6 2,91 5 R ASE Edwin P. Sundhohn,Albert City, Iowa Filed July 1, 1957, Ser. No. 669,230 (C 22-38 5 Thisinvention relates to a multi-fill grease application is acontinuation-in-part of my'eopending application, Serial No. 636,971,filed January 2 9 19, 57, now Patent No. 2,915,226. dated Deeember- 1,19,59,

\ There are at least three common methods of filling grease guns. In thepressure fill method, bulk grease-is pumped into the barrel of thegrease gun through opening in the dispensinghead. Alternatively, thegrease may be sucked into the grease gun. barrel. with the (lis pensinghead removed. Still another method is that of inserting the grease inthe form of a pre-paekaged cartrid'ge. From the standpoint offlexibility andrversatility This invention is shown in illustrativeembodiments in i the accompanying drawings, in whi ch-- Figurel is aside sectional view of agrease gun embodying the general principles ofthe present invention; Figure 2., is an enlarged sectional detailview ofthe, dispensing head of the grease gun of. Figure 1, taken on line 2-2-of Figure 1; Figure 3, a fragmentaryside sectional View of apreferred-"modification of the grease gun. in Figure 1; and Figure 4, isanother fragmentary side sectional view showing another. preferredmodification, of the grease gun in Figure l. 7

Looking first at the embodiment of Figures hand 2, there is shown agrease gun. which includesthe usual cylindrical grease container 10having a dispensing. head 11 detachably mounted on the forward end;thereof. The rear of the gun is. provided with a closure cap 12 which isthreadedly connected to. container 10, Within container 10 is aslidable' plunger assembly 14 having; a cup-shaped piston. or head:portion 15 arranged for urging grease toward dispensing head 11. In theillustration given, a compression spring 16 is disposed between the backof plunger assembly 14 and rear cap 12. If desired, however; the springcan beomitted.

In the embodiment of Figures 1 and,- 2, a ferrule or sleeve 17 ofslightly smaller diameter than the internal diameter of container 10' isdisposed in the rearward portion of the container. The open forward endof sleeve 17 is preferably arrangedv substantiallyconcentrically withthe bore of cylinder 10. Means are also provided for retracting plungerassembly 14 and more particularly head portion 15 thereof into theforward end of sleeve:1 7,- which in the illustration given includes aplunger rod 18 extending from plunger head portion. 14 through the rearwall'of cap 12.

2,978,151 ,Patent d An 1 1 as illustrated in Figures. '1 and 2, thesidewall portions beingdesignated by the number 15a. It will be notedthat the. side walls 151: of the piston terminate. in an annular portion15b which engages the inner walls of container 10 as indicated in Figurel. Preferably, the outer surface of the piston side wall issubstantially smooth and the inner surface thereof is provided. with aninwardly-extending ridge, as indicated by the reference numeral 150.Ridge portion 15c is substantially opposite the container wall engagig-Portion of the .outer surface of. the piston side wall 15a. It will beunderstood that the outermost portion of the piston side walls will havea. slightly greater exterior diameter; than.- the interior diameter ofcontainerv 10 to maintain the desired sealing relationship between thesecontacting surfaces. Also, the. inwardrnost portion of piston side walls15a shouldhave an exterior diameterv such that the piston 15 can bewithdrawnand compressed within sleeve 17 upon the. exertion ofsufficient force. thereon,

Plunger head assembly 15 may take variousv forms while. still achievingthe benefits of the present invention. In the illustrations given inFigures 1 and 2, the transverse body portion of piston 15 is clampedbetween front washer 19 and rear washer 20, these. members beinginterlocked to prevent any lateral shifting, of piston 15. Intheillustration given, a headed plug zl extends-through the unites washers19 and 20 and the body portion of piston. 15; For the purpose ofpermitting, plunger rod 18 to, move downwardly into container 10independently of the downward movement of plunger head assembly 14, thehead portion of plug. 21 is provided with a T- shaped slot 22, and the.outer end of rod 1.8is' provided with a laterally extending. pin 23..Since this means of releasably attaching a plunger assembly to a rod "isold and well=known in grease guns, it is not believed that it benecessary to further describe it herein. a

For convenience of assembly and operation, as shown in: the specificembodiments in Figures 1 and 2, rear cap 12 can be formed to provide arearwardly extending tubular portion 121:- of substantially the sameinternal diameter. as. the external diameter of sleeve 17, therebypermitting the rearward portion of the sleeve to be receivedwithin the.tubular portion of the cap. in tight frictional engagement therewith.The mounting of sleeve 17 within the tubular portion 12a by means of apress fit serves the purpose of holding sleeve -17 in fixed, concentricrelation to container 10, while providinganannular space 24 between theoutside of the forward portion of sleeve 17 and. the inside of therearward portion of container 10. In the illustration. given, cap 12also provides a skirt portion 1212, the skirt portion being forwardly ofthe tubular portion 12a for being. threadedly received over the outsideof the rear end portion of container. 10. Cap 12 also preferablyprovides an inwardly extending shoulder portion so that a sealing gasket25'can. be clamped between the inner wall of the cap shoulder portion atthe rear end. of container 10 to seal off the threaded connection from;the interior of container 10. If desired, however, sealingagasket. 25can be omitted for reasons which will subsequently be explained.

For the purpose of the present invention, the construction of thedispensing'head is of no particular importance providing the head isdetachable from the grease container and that it provides an inlet forpumping grease into the container through the head. For example,dispensing head 11, shown in Figures 1 and 2, includes a body 26 havinga bore 27 therein for slidably receiving a piston plunger 28 thatextends outwardly beyond body- '26 and is pivotally connected to a leverarm 29. The

forward end of lever 29 is pivotally connected to a pair of links 30,which in turnare pivotally mounted on body '26, thereby permittingpiston 28 to be reciprocated by the corresponding reciprocation of lever29. The bore 27 communicates with an inlet opening 31 which extendsthrough cap portion 32 and the adjacent wall of body 26 26 also providesan opening 33 communicating with the end of bore 27 towards which pistonrod 28 advances.

A grease discharge fitting 34 is threadedly received with- 'in opening33 provides a passage for the outflow of grease, and includes aspring-biased check valve 35 which is arranged to permit outflow only.The outer end of gating 34 is adapted to receive a grease applicatorpipe As shown more clearly in Figure 2, the transverse wall of cap 32 isprovided with an inlet opening 37, which in the illustration given, isinternally threaded to receive a filler fitting 38 and thereby mount thesame on the outside of head 11 to provide a passage extending from theoutside to the inside of container 10. Preferably, fitting 38 includes aspring-urged check valve 39 arranged to permit only inflow.

In one method of filling the grease gun of Figures 1 and 2, grease ispumped into container 10 through fitting 38. In this operation, as thegrease is forced in under pressure plunger assembly 14 will be drivenrearwardly. The pumping is preferably continued until the plungerassembly 14 reaches approximately the position illustrated in Figure 1,where the rear end of piston has just begun to enter the mouth of sleeve17. At this point, 'there will be increased resistance to the furtherrearward movement of the plunger, and this will require greater exertionof effort by the person operating the filling pump. This can be used asa signal to the operator to discontinue the pumping. Further pumpingwould have the result of forcing the plunger head within sleeve 17,thereby separating the piston 15 from the inner walls of container 10,and permitting grease to flow into the annular space 24.

In the filling operation just described, sleeve 17 has the function ofrestricting the rearward movement of piston 15. The sleeve 17 would alsoserve this purpose in connection with a suction filling operationwherein dispensing head 11 was removed, and grease was being sucked intocontainer 10 by drawing plunger assembly 14 toward the rear by means ofplunger rod 18. Whenever it is desired to insert a grease cartridgewithin container 10, however, this can readily be done by exertingsufiicient force on plunger 14 to withdraw it within sleeve 17. Upon theintroduction of the grease cartridge, the piston 15 will then beautomatically inserted within the open rear end of the grease cartridge,as described more fully in my co-pending application Serial No.

636,971, filed January 29, 1957.

of the cup-shape piston to restrict further rearward movement of thepiston while maintaining the engagement between the piston and the innerwalls of the container.

In the modified constructions of Figures 3 and 4 the parts correspondingto those of the construction of Figures -1 and 2 have been given thesame numbers except that the numbers in Figure 3 have been primed and inFigure v4 double primed to indicate that they are applied tomodifications. It will be noted that in the constructions of bothFigures 3 and the cup-shaped pistons 15' and side walls 15a and 15a andpositively stop any further piston side walls 4 15" have been reversedso that the outwardly flarin sides 15a and 15a" extend toward the rearof the gun. In the Figure 3 modification, sleeve 17 has been shortenedso that the annular space or pocket 24 is adapted to just receive theoutermost portion of piston side walls 15a. As shown in Figure 3, thisarrangement provides a positive stop for the rearward movement of theplunger assembly 14.

Similarly, in the construction of Figure 4, the sleeve or ring 17" isarranged to provide a pocket 24" for receiving the outer extremity ofpiston side walls 15a". Ring 17", as shown in Figure 4, has an angularcross section so that it can be clamped between rear cap shoulder 12c"and sealing gasket 25", the forwardlyextending portion of sleeve 17"being inclined inwardly to correspond with the taper of the inner lipportion of piston side walls 15a". The way in which this arrangementacts as a positive stop for the rearward movement of plunger assembly14" is illustrated in Figure 4.

In using grease guns employing constructions like that illustrated inFigures 3 and 4, grease can be pumped into the grease containers in theusual way, and the pumping continued without any particular concern asto whether grease will be forced between the side walls of the pistonand the grease container, which if it occurred would allow the grease topass behind the plunger assembly, covering the spring and other partswith grease, and even permitting grease to escape through the rear cap.The annular pockets 24' and 24", as indicated above,.will receive theoutermost portion of the piston rearward movement of the plungerassemblies 14' and 14". When this occurs the further introduction ofgrease can be discontinued, and even if an attempt is made to pump inadditional amounts of grease, the seal between 'the pistons 15' or 15"and the inner walls of. containers 10 and 10" will be maintained. Thesleeves 17' and 17" are arranged to provide and maintain the desiredsealing relationship. As an added precaution, the annular pockets 24 and24" are dimensioned so that the tip end of the 15a and 15a" can comeinto sealing engagement with the gaskets 25' and 25" which arepositioned respectively at the bottoms of pockets 24' and 25".

The modifications of Figures 3 and 4 can also be used where it isdesired to fill grease guns with cartridge packaged greases. Byemploying pistons which have outwardly flaring side walls extendingtoward the rear of the guns, the pistons are self-inserting with respectto the grease cartridges. Also, grease can be sucked into gunsconstructed like those shown in Figures 3 and 4. In fact, the reversingof the pistons will provide an increased suction effect, and willtherefore improve the suction filling action of such guns.

While in the foregoing specification this invention has been describedwith reference to specific embodiments thereof and many details havebeen set forth with respect to these embodiments, it will be understoodby those skilled in the art that the invention is susceptible to otherembodiments and that many of the specific details described herein canbe varied considerably without departing from the basic concepts andprinciples of the invention.

I claim:

1. In a grease gun adapted for both pressure and suction filling andincluding a cylindrical grease container "having front and rear ends, adispensing head removably mounted on the front of said container, saiddispensing head providing an inlet opening through which grease can bepumped into the frontward portion of said container, and a slidableplunger assembly within said container "arranged for movement away fromand towards said aeralei the inner walls of said container, all othercomponentsof said plunger assembly being spaced inwardly from the saidinner walls of said container, and annular positive stop means disposedwithin the rearward portion of said container in the path of rearwardmovement of said outwardmost portion of said piston side walls, saidstop means cooperating with said outwardmost side wall portion of saidpiston to restrict further rearward movement of said piston whilemaintaining the engagement between said annular portion and the innerwalls of said container.

2.. In a grease gun adapted for both pressure and suction fillingincluding a cylindrical grease container having front and rear ends, adispensing head removably mounted on the front end of said container,said dispensing head providing an inlet opening through which grease canbe pumped into the frontward portion of said container, a slidableplunger assembly within said container arranged for movement away fromand toward said dispensing head, said plunger assembly comprising acup-shaped piston of flexible, resilient material arranged in concentricrelation to the inner walls of said container, said piston havingoutwardly flaring side walls extending toward the rear end of saidcontainer and terminating in an annular portion in engagement with theinner walls of said container, all other components of said plungerassembly being spaced inwardly from the said inner walls of saidcontainer, and means disposed within the rearward portion of saidcontainer cooperating with the said outwardly flaring side walls of saidpiston to restrict further rearward movement of said piston whilemaintaining the engagement between said annular portion and the innerwalls of said container. 7

3-. The combination of claim 2 wherein said restricting means comprisesa ring mounted in the rearward portion of said container, said ringhaving a frontward end portion spaced inwardly from the inner walls ofsaid container to provide an annular pocket therebetween for receivingthe outermost portion of said flared piston side walls.

References Cited in the file of this patent UNITED STATES PATENTS

